The implementation of cover crops in crop rotation is a suggested soil health practice. As cover crops are not harvested and sold, they do not directly provide monetary gain to producers. Therefore, it is imperative that planting cover crops does not negatively affect the subsequent cash crop. However, there is no overall consensus in the literature regarding the effects of cover crops on cash crop yield. To better understand the effects of cover crops on soybean growth and yield in Oklahoma soybean systems, trials were conducted in Bixby, OK, in 2019 and Perkins, OK, in 2019, 2020, and 2021. The objectives of these trials were to (1) determine how different cover crop mixes affect soybean growth parameters and (2) determine if cover crops significantly influence soybean seed yield. Treatments within the trials included six cover crops and a fallow treatment. Soybeans were planted after the termination of the cover crops. Yield and growth parameter data were collected after harvest. No significant differences or consistent trends were detected in the yield among treatments. While cover crops had a significant impact on the number of three- and four-bean pods, no other differences in the growth parameters existed, and they never translated into significant yield differences. Based on our data, cover crops would not benefit the overall cash crop production in the continuous cover crop soybean system in Oklahoma. However, the fact that cover crops did not consistently or significantly reduce soybean yield allows growers to explore other benefits, such as weed management or soil health improvement.

Soybean production in the southern Great Plains (SGP) faces challenges due to yield-limiting factors, including high temperatures and inconsistent precipitation. These conditions can lead to excess vegetative growth, similar to what occurs in crops like cotton. Management strategies utilizing plant growth regulators (PGRs) have been applied to control this excessive growth, yet there is limited information on methods to mitigate vegetative growth in soybeans through modifications to the apical meristem. Field trials conducted in 2022 and 2023 investigated the effects of altering the apical growth using Ascend SL, Compact, Cobra, Cygin Pro, and physical removal, with treatments applied at the V4 and R2 growth stages. This study highlights the significance of customized application strategies to enhance profitability under diverse environmental conditions. Ascend and Cygin Pro demonstrate improving yield stability under adverse climatic conditions. Both applications of Compact produced relatively stable yields across site years, while Cobra and physical removal methods necessitate careful consideration of timing to minimize yield losses. Further research is essential to optimize these management strategies for soybean production in the SGP.

Planting density can influence the growth and potential yield of grain sorghum systems, particularly in resource-limited environments. Therefore, documenting the sorghum’s response to different planting densities is essential for understanding crop behavior in relation to optimal yields. A study was conducted in Lahoma and Perkins, Oklahoma, in 2019 and 2020 to assess the impact of varying planting densities and within-row planting in-row gaps. Planting density varied from 43,225 to 223,500 plants ha⁻¹. Three additional treatments were implemented at 148,000 plants ha⁻¹ with 0.3, 0.6, and 0.9 m gaps. An increase in plant density resulted in higher yields at Lahoma in 2019. However, at Perkins in 2019 and 2020, yields were optimized at 148,000 and 111,000 plants ha⁻¹, respectively, and decreased as planting densities diminished. In-row gaps of 0.3 and 0.6 m did not significantly affect yields across all site-years; however, at Perkins, the 0.9 m gap significantly reduced yields compared to stands without gaps in both years. Overall, a direct relationship was observed between sorghum yields and planting density. Further evaluation of in-row gaps and how planting management should be adjusted is warranted based on the presented information.

Plant mapping was introduced in soybean, but its illustrative capabilities in stress response are yet to be implemented. Methods to track the soybean physiological response are explained in this note by mapping pods in a coordinate system. A growth chamber study was conducted to measure the specific impact of simulated moisture stress on crop yield and pod development across three stages of crop growth. The treatment growth stages were R2, R3, and R5 (Full Bloom, Beginning Pod, and Beginning Seed, respectively), with two moisture stress durations of 7 and 14 days. A coordinate system was developed to understand soybean pod setting and yield by plotting each unique point on the plant using a set of numerical coordinates. This method summarizes soybean morphology during its vegetative and reproductive growth. Utilizing this method, we found that the growth stages during which moisture stress is experienced and the duration of the stress determined and influenced the location of pods on the soybean plant. The stress level factors impact the yield on the mainstem and branches by pod capacity at different magnitudes. This encoding procedure assists in tracking the location of aborted pods. It protects the yield by retaining pods, thereby leading to a better understanding of the stress experienced by these plants.